Regulating system for fluid supplies



I July 21, 1931. L. DE FLOREZ REGULATING SYSTEM FOR FLUID SUPPLIES Original Filed Jan. 21, 1926 4 Sheets-Sheet l mJBU NQSK awvmtoz July 21, 1931.

L. DE FLOREZ REGULATING SYSTEM FOR FLUID SUPPLIES 4 Sheets-Shet 2 Original Filed Jan. 21

Fl- I I avwwdcoz ABM/LBW July 21, 1931. DE FLOREZ REGULATING SYSTEM FOR FLUID SUPPLIES Original Filed Jan. 21, 192 4 Sheets-Sheet 3 auoautoz pa W a? v RXOW July 21, 1931. 1 L. DE FLOREZ 1 REGULATING' SYSTEM FOR FLUID SUPPLIES Original Filed Jan. 21, 1925 4 Sheets-Sheet 4 .supku L/IVE SUPPLY sou/w:

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\ .'directly by variations in the i set forth of the control -Patented July 21, 1931' 1 UNITED STATE-S THE TEXAS COMPANY, OF NEW .PA TEN'l OFFICE.

LUIS DE rronnz, or romrnn'r, connncrrcur, assrenon, BY mn vsn hssienmnn'rs, T

YORK, 1v. Y., A conroaa'rron or, DELAWARE- v nizeuna'riuo sSzsrEM roe FLUID sUrrLI'E s Continuation of application Serial No. 82,865, filed January 21,1926. This application filed June 12, 1930. a X 1 Serial No. 460,621.

- My invention relates to a method and -means for controlling a fluid in response to variations in the value of a condition and in one of its aspects maybe regarded as the 5 control of the flow of a fluid by efl'ecting the control of the head of the controlled-fluid in response to variations in the value of the condition. Such control may be used to maintain the'floiv of the controlled fluid at a subo'stantially uniform rateor it may be used L to cause variations thereof which are functions of thevariations in the value of the condition. v

The condition, the values of which are efl'ectiye to supervise .or determine the control of the. fluid flow in the fluid supply system, may be the condition of pressure, or of temperature, or of any other suitable factor. The variations in-the value of this condition may be dependent upon the variations of the flow of,the controlled fluid, as for instance, in the case of a pyrometer aifected introlled fuel, or the variations in the value of the condition may be wholl independent of any reaction caused by the uidflow. As an example of the latter, the control of the fluid flow in the supply system may be in response to variations in the temperature, or pressure, or other condition, which is entirely independent of the fluid s stem under control so that the flow of 'fl iiid under control shall be proportionate to the change of condition in the parallel flow-' independent of the controlled fluid flow may be setup by an operator or mechanism at some remote point, such as a central station, in response to which condition changes, the flow of fluid is controlled. In the case of (these and other examples which mightbe of'the fluid flow in response to changes in the value ofa condition which is independent 'ofthe fluidflow,

may be arbitrarywitli reference to any effect of a parallel flowing fluid ing fluid; likewise, changes in a condition the term arbitrarily has been employed insome of the claims to include this type of 'control as well aswhere p ndent upon the flow. The controlefi'ected;

In the preferred embodiment of my invention the control of the flow of the eontrolled fluid may be effected by operating upon the head of the controlled fluid in response to variations of anintermediate eon trolling mechanism. This'intermediateconmeans of theysupervisory control. Such intermediate controllingmechanism may be a current responsive device, such, for instance, .as an electric or fluid motor controlled by variations of the supervisory control, which may comprise, for instance, a pyrometer or other heat responsive device, and the. control effected by the supervisory control of the intermediatecontrol may be the control of the flow of current (fluid or electric) to the intermediate controlling device. I It has heretofore been common in the rior art to control'the amount of fluid, as or instance, fuel passing to a furnace, or other apparatus to be heated, by merely varying the port opening of a valve in the .fuel delivery line in proportion to the desires change in the amount of fuel. By varying the port opening of the customary umopen valve be closed to a point to give onehalf theport opening it had whenfull :open,

the amount of fluid which will pass t rough .the valve will be greater than one-half thethe-condition is de-fi -lamount, delivered by# the valve in the full open position, assuming a substantially co e stant .,pressure of the fluid. supply,- source.

90. in the amount of the fueldelivered is not obtained.- Thus, for example, ifvthe fully tal when it is desired to accurately control the amount of fluid delivered past the valve or, in other words, to control the flow of the fluid on the delivery side of the valve.

In accordance with my invention, I can control theflnid flow independently of any particular setting of the valve between the source of fluid supply and the controlled supply line, since I operate directly to control the pressure head on the delivery side of the valve and consequently to .control the primary factor which determines the rate of fluid flow. In other-word's, I do not attempt to vary specifically the port opening of the 'valve but the desired result is accomplished by making the valve responsive to the pressure head on the delivery side of the valve in such a manner that with a given setting of the control mechanism it tends to maintain a constant delivery pressure, the valve port opening automatically adjusting itself to whatever position may be required for the purpose. To definitely change the pressure head, and consequently the flow, as may be called for by the supervisory control, the relationship of the control mechanism setting to the pressure head is'changed. It will thus be seen that my invention also provides for automatically compensating for variations in the supply source pressure by varying the port opening of. the valve between the source of supply and the supply line.

Thus in accordance with my invention I accomplish the control of flow by controlling the mean pressure'on' the delivery side of the valve in response to changes of. the supervisory control and I also independently vary the port opening to compensate for any changes which may take place in the fluid pressure of the supply source. By the application of my invention I am enabled to obtain an accurate control of the fluid flow and it will be observed that my invention, therefore, permits the regulation of the fluid flow by effecting a regulation of the mean delivery pressure without regard necessarily to the area of the valve port opening. j

The type of supervisory control, which may be applied in the preferred embodiment of my invention to the regulation of the'c urrent (fluid or electric) actuating the intermediate control, may vary widely, ac-

cording to the conditions under which the apparatus is designed to operate. I may, for instance, use a swltch or valve-actuated by the supervisory control and remaining in operative condition until disabled by a predetermined reading or change of condition of the supervisory control; I may use a type of control in which current is delivered in one direction or the other, suchv control being continuously operative and the direction of its correction being determined by the supervisory control; I may use a control j which 'the current to the intermediate controlling mechanism is incrementally applied in one or. both directions, suchincrements varying in the strength of the corrective iinpulse applied, or in the direction in which they areapplied, or in the duration of their application, orif desired two or more of such factors of regulation may be combined.

One type of system which I may employ to accomplish supervisory control responsive to changes in the value of the condition is particularly well suited to its purpose and provides periodical impulses which bear a definite relationship to the departure of the value of ihe condition from the predetermined or selected value. The intermediate control which cooperates with the supervisory control may comprise a major control and a minor control which cooperate'to produce the desired result. The minorcontrol makes corrections preferably periodically from a base previously established by the major control, but when these corrections add in one direction to a predetermined sum, the major control becomes operative to change the base. From this new base the minor control thereafter operates until the minor corrections ,again amount tothe predetermined sum. The major andminor' controls are operated preferably by electrical energy supplied responsively to the supervisory control and an additional important feature of they supervisory control system, therefore, comprises means which are adapted to make periodical contact for periods of time, each of which are preferably proportional to the departure of the valueof the condition fronrthe predetermined value. Thus, for example, in the control of temperature, if the temperature is close to the predetermined er desired-temperature, only a short period of contact will result and a correspondingly small correction will be made in the supply line pressure head; on the other hand, if the departure of temperature from that desired has been great, a longer period of contact will result and-a large correction will be made.

Further advantages of my invention will becomeapparent to those skilled in the art upon the examination of the followingspecificationand drawings. v

In the drawings Figure 1 is a diagrammatic illustration partiallyin section of my control system applied to the regulation of the temperature of coils in a furnace.

Figure 2 is a partially sectional elevation of the valve control mechanism.

Figure 3 is a plan view of a part of the valve control mechanism. v

chopp the needle 10"Wh1ch in turn may strike one sectional elevation Figure 4 isa artially th I t 1 e va we con ro of a modified orm o mechanism. I

I Figure 5 is a partially sectionalelevatlon 5 of another, modified form of the valve control mechanism.

v Inthe various fi ures' ofv the drawin'gsthe same numerals in icate like parts pf the apparatus. v I

In Figure 1,) indicatesthe valve control mechanism for .afiecting the position of the valve in the valve casing'2. This valve conv trols'the flow of fluid fuel from the supply source, which ma be from a gas mainor an 15 oil tank or any it er suitable source. Supply line 3 leads the fuel to the burner shown diagrammatically at 4, situated in an opening in the wall of the furnace 5. The control system is illustrated in Figure 1 ascontrol- 2o ling the temperature at the outlet 6 of the pipe coils 7 throughwhich oil may be passing to be heated by; the furnace 5 to a crackmgtemperature. A thermo-couple 8, or'other sultable temperature reflectmg device, is situ- 26 ated at the point whose temperature is to controlled. The [leads from this therm'm couple are connected to a galvanometer or potentiometer system shown diagrammatically at 9 in the manner wellknown 1n the 80 art. The galvanometer needle is indicated at 10 and is positioned'so as to move in ahorizon'tal plane Switch members 11 and 12 are pivotally mounted within the range of movement of the galvanometer needle 10 but in a 5 51m slightly above the plane in which the needlenorm'ally moves. The switch members are provided with adjustable stops 13 and 14 against which. they are normally held by springs or other resilient means. Belowthe glalvanometer needle 10 there is provided a 0 er 15 operated continuously any suita le mechanism illustrated diagram-4 matically 'at '16, periodically causing the er to be 'broughtjinto contact with of the member-s11 or 12 and deflectthesame.

', This, of course,does not occur'if the needle 10 is in a-central positionbetween the memalbers-ll and 12 corresponding to the predee termined or selected temperature. The mem- "bers 11' and 12 are connected respectively to "conductors 17 and.18, which in turn are connected'to solenoids19, adapted to close the switches 20. These switches are normally retained in open position by springs. The solenoids 19 have a common terminal which is connected by conductor 21 to one of the -terminals of a source of electrical energy ilea lustrated diagrammatically by the generator 22. The other terminal of-the generator 22 is connected by conductor 23 tochopper 15. The switches control the energization'ofthe 1 motors 24 and 25 which are connected in I parallel and .which'receive power through the conductors 26 .from any suitable source (not shown).

B the periodical upward movement of I the chopper 15 the galvanometer needle 10 may be brought into contact with one of the membersll or 12 depending upon the direc-v tion in which it has been deflected by a change in temperature responsive to the thermo-couple 8. The contacting of cho per 15, galvanometerneedle.10'and one o the members 11 or 12, closes one ofthe circuits through conductors 17 or 18 to energize one of the solenoids 19, which will in turn close the switch controlled b it. It will be observed that the inner en s of members 11 and 12 are curved upwardly and they thus give.

a period of contact which varies with the extent of the deflection of the galvanometer I needle from its normal position representing I the normal temperature. Consequently the .periods' of time for which the motors 24 and 125 are energized will be dependent upon the iextent of the departure of the temperature in the outlet 6 from the desired temperature; .I may lise other apparatus to obtain periods of contact proportional to the variation of the value of a condition from normal,

such as the devices described in my .copending application Serial 'No. 579,603, filed valve 30 is suspen on the valve stem 31,

which is attached to and supported by the diaphragm, 32 in the diaphragm casing i 33. The diaphragm casing 33 is mountedon the casing 34, which in turn is rigidly supported by the valve casing 2. The motors 24 and 25 also are rigidly supported by the I casings '33 and 34. v

The shaft of the motor 24 is connected to a worm35and by; the rotation of the motor 24 corresponding motion is transmitted through the worm and gear train consisting 'of worms 35 and 37 and gears 36 and 38. Upon the shaft of the .gear 38 is loosely .mounted a Geneva stop pinion 39 having a pin 40 adapted to cooperate with the finger 41 which is keyed to the shaft 'of the gear 38, to turn the Geneva stop pinion 39 if and when the finger 41 is rotated the proper distame by operation of the motor 24 through "the worms andfgears 35, 37, 36 and 38. The

Geneva stop pinion 39 has a'single tooth 42.

which cooperates. with the Geneva stop wheel 43 to-move the same a fraction of. a

turn and it will be observed that a further movement of the wheel 43 will only take place after a complete revolution of'the finger 41. The teeth 44 of-the Geneva stop I wheel 43 are formed with concave surfaces seat for one end of a compression spring 51.

, The other end of the spring 51 presses against the lower side of the diaphragm 32 while the coils of the spring encircle the valve stem 31. A member 52-is rotatably mounted on a portion of the casing 34 which serves as a bearing therefor. The member 52 is internally threaded to cooperate with the sleeve 50 which is externally threaded so that the member 52 may freely rotate to raise or lower the position of the sleeve 50. The wheel 43 rests on the upper side ofa flange on the member 52, while the wheel 43 and member 52 are firmly but yieldingly held against each other by a stiff spring 53 compressed between the lower side of the flange and an extension of the wheel 43. This compels transmission of any movements of the wheel 43 into corresponding movements of the member 52. I

An arm 54 is mounted on the shaft of the motor 25 yieldingly eonnected to one end of the lever 55 by a link and springs 56. Lever 55 is pivoted at 57 and the other end of the lever cooperates with the slidable collar 58 on the valve stem 31. The collar 58 is so secured to the spring 51 that any movements of the lever 55 serve to increaseor decrease the pressure of the spring 51 against the diaphragm 32. The dash pot 59, suspended from the diaphragm casing 33 is also connected to lever 55 and prevents too sudden a movement' of this member. An additional important function of the dash pot 59 is to prevent a sudden reaction upon the diaphragm 32 through the pipe 60 because of any temporary puffs of pressure which may, by design, be created by the application of the corrections effected by the motor 25. Thus when a momentary correction 'is made to increase the port opening of the valve 30 the spring 51 is pressed upwardly by the lever 55, This increased pressure of" the spring 51 raises the diaphragm 32 and causesthe valve 30 to open further. 'This movement of the valve will cause a momentary increase in the pressure in the supply line 3 which would immediately be reflected through the pipe 60 to the upper diaphragm chamber and would tend to close the valve 30 by depressing the diaphragm 32 and pressing downwardly on the lever through spring 51. The dash pot 59, however, will tend to prevent this action by allowing the lever 55 to return only slowly to its normal position.

A pipe forms a connection between the supply line 3 and the. upper chamber of the diaphragm so as to change the position of the valve 30 if any unusual fluctuation in the supply line pressure occurs. Pipe 60 may be provided with a valvet48 to control the'pase sage of fluid therethrough.

The operation of the valve control mechanism shown in Figure 2 is as follows: As previously described the motors 24 and 25 are in parallel and periodically receive impulses in one direction or the otherby the closing of one or the other of the switches 20 in response to the periodicalcontact-ing mechanism shown in Figure 1. In the preferred embodiment of my invention the contacting mechanism makes contacts which are proportional to thedeparture of the temperature from the predetermined temperature, but this relationship may bear any other fixed relationship to the changes in the value of the condition. WVhen the motor 24 is thus energized it is only for a short period of time and through the worm and gear train will move the finger 41 v a short distance. No

movement of the Geneva stop pinion 49 will stop pinion 49 to move the Genevastopwheel 43 a fraction of a turn represented by the width of one of the teeth 44, it will beobserved from the foregoing description that a complete revolution in either direction of the finger 41 will be required to cause a further movement of the wheel 43. As previously pointed out both positiveand negative corrections are made, depending upon the direction in which the'galvanometer needle moves from the central point in response to changes in the temperature. Consequently the finger 41 maybe moved in either a clockwise or counter-clockwise direction without completing a revolution and therefore without causing a movement of the wheel 43. In fact when the regulation of the system has become more orless stabilized the number of major corrections will become quite infrequent and the finger 41 will move back and forth without effecting a movement of the wheel 43. When the Geneva stop wheel 43 is moved a fraction of a turn this movement is transmitted through the spring 53 to the member 52 which screws the sleeve 50 up or down, depending upon the direction of the correction to be applied. This change in the position of the sleeve 50 changes the comin the setting of the valve 30 by movements of the motor 24 consti tute the major corrections in the valve setting.

1 heretofore pointed out.

. When the motor is energized its move- The corrections in the valve setting which may be induced by movements of the motor 25 constitute the minor corrections which are effective to change the flow of fluid with each periodical contact of the contacting mechanism. It is to be understood that these corrections follow each other at frequent intervals but" it will be observed that after each of the corrections,-thus applied, the pressure head returns to the value determined b the rotation of the motor 24 acting throug the spring 51 and diaphragm 32. If, during-the operation of the above described supervisory control and intermediate'controlmechanisms,

a change should occur in the pressure of the fluid supply source-a similar change would take place in the rate of flow in the supply line. To compensate for such changes the pipe 60 immediately reflects any changes in pressure to the upperchamber of the diacausing a corresponding change in I the position of the diaphragm 32 and through the valve stem 31 in the position of the valve 30. Thus, for example, if the pressure of the fluid supply source increases the diaphragm 32 will be depressed and the valve 30 will. consequently be partially closed to, offset or compensate for this increase in fluid supply pressure. The'opposite effect is produced if the-supply pressure decreases.

It becomes ObVlOllS from the foregoing de-' scription that'the diaphragm 32 serves as a means for balancing opposing forces and of establishing the desired pressure head in the supply line. One of-these forces consists in the pressure applied to the upper side of the diaphragm 32 (in Figure 2-) by the fluid through the piple which connects with the supply line 3. he'secofrd force which serves to balance the first force, when the diaphragm 32 is in a state of equilibrium, is furnished the diaphragm '32. Either of these two forces by the spring 51 pressingupwardly against may change and, unless the change be equal and simultaneous, the position of the dia-. phragm '32 will be changed and, since the valve 30 is directly connected by the valve stem 31 to the diaphragm 32, the position of the valve will be altered. Thus if any fluctuation occurs in the pressure of the supply source this will immediately -,be reflected through the pipe 60 to the upper diaphragm chamber and the port opening of the valve 30 will be changed to compensate for this change in pressure, again restoring the pressure in the supply line 3 to that-desired. On the other hand, the second force may be changed as called for by the supervisory con-' trol and, to restore the balance between the two opposing forces, a greater or lesser pressure will be required in the upper diaphragm chamber. Assuming a constant pressure of the supply source, this change of course will be brought about by a change in the valve port opening. It is conceivable, however, that if an increase lllftlle rate of flow and consequently in the pressure head of the supply line 3 should be called-for by the supervisory control and an increase of the desired amount, should occur simultaneously in the pressure of the supply source, obviouslyno movement of the valve 30 would occur to supply the desired increase in the flow. It is apparent, therefore, that I am'enabled by my invention, as previously ointed out, to control the flow in the supp yline without regard necessarily to a specific valve port opening. I

In'Figure 4 the supply line is connected by pipe 60 to a passage 61 which leads to the lower; chamber of the diaphragm 32.

This allows fluctuations in the supply line pressure to vary the valve setting as in the apparatus shown in Figure 2. In the modification of Figure 4 the motor 25 is mounted centrally and has a lever 62 fixed to the factor shaft for operating bynnovement ofthe motor and lever and poppet valves 63 and 64 in the pipes 65 and 66. 'Pipe 66' is connected to the fluid supply source and leads to the lower chamber of the diaphragm 32. Pipe 65 leads I from this chamber and since it is an exhaust pipe it may lead to a separate burnerin the furnace, in the case where the fluid being regulated is a fuel, or in other cases to any suitable exhaust point. It will be'observed that, by the opening of. the valve 64, fluid under pressure will flow into the lower diaphragm chamber and tend to raise the-diaphragm 32 and partially close the valve 30.

This action of course occurs when the supply line pressure becomes too great. On the other hand, if the supply line pressure decreases below the desired point the motor 25 will open the valve 63 and permit the diaphragm to lower, opening the valve 30.

A beam 67 is pivotally supported at 68 on the diaphragm casing and has a knife edge 69 which rests on the standard 70. The stand-' ard 76 is rigidly secured to the diaphragm 32. The beam 67 is provided with manually movable weights 71 for asserting a predetermined pressure u n the standard 70 and hence upon the diaphragm 32. In addition there is from the supply source will be admitted to before by means of the motor 25.

in a manner similar to that of Figure 2. Ma-

jor correctionsare applied by movements of the motor 24 which operates to change the position of the weight 72 bymovements of the worm 7 3. A movementof the weight 72, however, only occurs when the Geneva stop wheel is given a fraction of a turn as previously described in detail. the position of the weight 72 the downward pressure exerted on the diaphragm 32 is similarly varied and the setting of the valve 30 is changed. Minor corrections are applied as If this m o tor tends to turn in a clockwise direction, the valve 64 will be opened and some of the fluid the lower diaphragm chamber. This will have the effect of raisin'g the' diaphragm which in turn will partially close the valve 30. By a movement of the motor in a counterclockwise direction, the valve'63 is opened,

which eizhausts a partof the fluid in the lower diaphragm a chamber and permits a ,corresponding opening of the valve 3O. As in the mechanism shown in Figure 2, the pipe 60 serves to compensate for any changes which may occur in the fluid supply pressure. In

this figure, however, the p1pe 60 is connected to the lower diaphragm chamber through the passage 61 and consequently an increase in the pressure will immediately effect a raising of the diaphragm 32 and a partial closing of the valve 30. The opposite effect is produced by a decrease in the pressure of the fluid supply source.

In the form of mechanism shown in Figure 5 a single'type of correction is applied in response to the supervisory control system to the pressure head, e'xclusive of the pressure compensation achieved through means of the p1pe leading from the supply line 3 to t scribe On the shaft of the motor 80 is a 82 mounted on a flange on the member 52. The worm wheel 82 is firmly but yieldingly Corrections are applied by the motor 80 in 1 response to impulses from the periodical conflenergized fora tacting mechanism and the motor being 52 through' means of the worm 81, worm By changing cated in the appended claims.

e upper diaphragm chamber. This pressure compensating device operates. .to varg the valve setting as previously deternally threaded to cooperate with the member 52. The change in the positionof the sleeve 50' changes the compression of the spring 51 and may establish through the.

valve stem 31 a corrected setting of-the valve in the valve casing 2.

This application is a continuation of my application Serial No. 82,865, filed January 21, 1926.

While I havefspecifically described and illustrated certain means for'accomplishing the principles of my invention, itgis obvious that various other embodiments might be evolved by those skilled in the art and I, therefore, desire to be limited What I claim is: Y Y i I 1. Inafluid system, a. source of fluid supply, a point of fluid use, a supply line connecting the source of supply with the point of use, means between the source of supply and the supply line for maintaining a substantially uniform head in the supply line,

current operated means adapted to cooperate with said first means to effect continuing changes in the supply line head,.a second current operated means adapted to cooperate with said first means to effect temporary changes in the supply line head, and means responsive to changes in the value of a condition from a predetermined value for controlling the operation of both said current operated means.

' ,2. In a fluid fuel supply system, a furnace or the like, a burner for heating th furnace, a source of fuel supply, a supply lin connecting the source'of supply with the burner, a valve between the supply source andthe supply line, means to actuate the valve to maintain a substantially uniform head in the supply line, current operated means adapted to cooperate with said first means to effect continuing changes in the supply-line head, a second current operated means adapted to cooperate with said first means to effect temporary changes in the supply line-head,'-and means responsive to changes from a predetermined temperature ataselected point in the furnace for controlling the operation of both said current operated means, whereby the temperature of thefurnace at the selected point will be maintained substantially constant.

3. The process of regulating the flow of a fluid in a fluid system, which comprises estabonly as indilishing a substantially uniform head .in the system, and automatically and arbitrarily varying the head at suitable periodicintervals, from that previously established, respons'ively to changes from a predetermined value in a condition, wherieby the flow of fluid in the system is maintained in predetermined relationship to changes in the value of the condition. v

4. In a fluid systemfa source of fluid supply, a point of fluid 1 se, a supply line conmeeting the source of supply with the point. of use, means between the source of supply and the supply line for maintaining a sub- ,stantially'uniform'h-ead in the supply line,

ply, a point & fluid use, a supply line c'onnecting the source of supply with the point of use, means between the source of supply and the supply line for inaintaininga substantially uniform head in the supply line,

, means to .determinechanges in the value of a condition, means for minor regulation to vary the head in the supply line, means to translate the changes in the value of the condition into proportional periods of time for which said 'means forminor regulation is actuated, and a major regulating means adapted to integrate the actuations of the minor regulating means and apply a major change to the head when said integration reaches a predetermined sum".

6. In the process of regulating the flow of a fluid in a fluid system, the steps which com- 'prise establishing a substantially uniform ead in the system, arbitrarily varying the head at suitable periodic intervals, from that first established, responsively to changes from a predetermined value in a condition, and after each such periodic variation elfecting a return to the first established head.

7. The process of regulating the flow of a fluid in a fluid system, which comprises estab-' lishing a' substantially uniform head in the system, arbitrarily effecting minor variations in the head, from that first established, re

sponsively to changes from a predetermined value in a condition, and when the minorvariations add in one direction to a prede termined sum, effecting a major change in the order of the head, whereby the flow'of fluid in the system is maintained in' predetermined relationship to changesin the'value of the condition.

8. The rocess of regulating the flow of a I fluid in a uid system, which comprises establishing a substantially uniform head in the system, arbitrarily effecting minor variations at suitable periodic intervals in the head, from that first established, responsively to changes from a predetermined value in a condition, effecting a return to the first established head after each such variation, and when the minor variations addin one direction to a prede-' termined sum, effecting a major chan e to establish a head of a different order, from which base minor variations may then be made.

9. The process of regulating the flow of av fluid fuel in a fuel supply system leading to a furnace orthe like, which comprises period-' ically varying the port opening of a valve in the fuel supply line, responsively to changes in the temperature at a selected point having a direct relation to the temperature of the furnace, and automatically controlling the port opening of said valve to'maintain substantially uniform the level of head determined by saidvariations, whereb the temperature is maintained substantial y constant at the selected point regardless of changes in head of the fuel supply source. 7

10. In a fluid s stem, :1 source of fluid supply, a point of fluid use, a supply line connect- 7 ing the source of supply with the point of use,

means between the source of supply and sup ply line for maintaining a substantially uniform head in-the supply line, means to determine changes in the value of a condition,

regulating means for varying the head in the r supply line responsive to changes in the value of the condition, and means controlled by said first means for varying the normal base level from which said regulating means is effective.

.11. In a fluid system, a source of fluid supply, a point of fluid use, a supply line connecting the source of supply with the point of use, means between the source of supply and supply line for maintaining a substantially uniform head in the supply line, means to determine changes in the value of a condition, regulating means for varying the head in the supply line, which means is proportionately responsive to changes in the value of the condition from a predetermined value, and means controlled bysaid first means forvarying the normal base level from which said regulating means is effective.

12. IIn a fluid system, a source of fluid sup ply, a point of fluid use, a supply line connecting the source of supply with the point of use, means between the source of supply and supply line for inaintainin a substantially uniform head in the supp y line, means to determine the changes in the value of a condition, regulating means for varying the head in the supply line responsive to changes in the value of the condition and having a limited range of effective regulation, and a second regulating means controlled by said first means cooperating'with said first regulating means and operative when the effective range of the latteris exceeded, to vary theinormal base level from which said first regulating means shall thereafter be effective.

13. The process of regulating the flow of I a fluid\in a fluid system which comprises establishing a substantially uniform head in the system, arbitrarily eifecting predetermined variations in the head, from that first established, responsively to changes from a 'predetermined value in a condition, and autolnatically varying also responsively to changes in theyalue of the condition the normal base levelfrom that previously established from which level said predetermined variations are thereafter eflective;

14. The process of regulating the flow of a fluid in a fluid system which comprises establishing a substantially uniform head. in the system, arbitrarily effecting predetermined variations in the head, from that first established, which are proportionately responsive to changes from a predetermined value in a condition, and automatically varying also responsively to changes in the value of the condition the normal base level from that preare thereafter effective.

viously established from which level said predetermined variations are thereafter ef- I fective.

15.The process of regulating the flow of a fluid in a fluid system which comprises establishing a substantially uniform head in the system, arbitrarily effecting predetermined variations 'over a limited range in the head, from that first established, responsively to changes from a predetermined value in a condition,'and when the effective range of said predetermined variations is exceeded, automatically varying also responsively to changes in the value of the condition the normal base level from that previously established from which level said predetermined variations 16. The process of regulating the flow of a fluid fuel in a fuel supply system leading to a furnace or the like which comprises establishing a substantially uniform head in the system, effecting predetermined variations 'over a limited range in the head, from that first established, responsively to changes in the temperature ata selected point having direct relation to the temperature of the furnace', and when theeffective range of said.

predetermined variations is exceeded, automatically varying also responsively to changes in the value of the condition the normal base level from that previously establishedfrom which level said predetermined variations are thereafter eflective.

In witness whereof I have hereunto set my hand this 11th day of June, 1930.

v LUIS DE FLOREZ.

gas. 

